Inflatable cushions are typically used for low impact applications, such as seat cushions and mattresses; or for high impact applications, such as padding to protect packages during shipment thereof.
Individuals who are confined to a bed or wheelchair for prolonged periods of time are susceptible to developing lesions in the nature of bed sores on the more vulnerable parts of their bodies. These individuals require a stable cushion or mattress that provides generally uniform pressure over the area of the cushion in contact with the individual's body.
When a cushion is used for low impact applications, such as for sitting in a wheelchair, it is desirable that the pressure in the cushion be such as to provide a relatively soft seating surface and yet one that is not overly responsive to sudden movement of the body thereon. It has been learned that when a person moves about on the upper surface of the cushion, a fluid reaction known as "surging" can result in a sudden collapse of the cushion in one area with a resultant rebound or commensurately rapid inflation in another area of the cushion. As a result of such surging and rebound, it is not unusual for the patient to get a feeling of bodily instability and discomfiture.
The seat cushion disclosed by Morner in U.S. Pat. No. 2,495,124 comprises two layers of adjacent inflated cells. Each cell is self-contained and does not communicate with any of the other cells. This type of cushion which does not provide for fluid flow to adjacent cells is unable to evenly distribute the pressure in the cells thereby localizing pressure to the user's body and which may result in bed sores.
The seat cushion disclosed in U.S. Pat. No. 2,434,641 attempts to resolve the problem of individuals developing skin lesions from sitting for protracted periods of time on air support cushions. In the '641 Patent a plurality of bellows of various diameters disposed in the cushion are interconnected. Unfortunately, cushions of this type would be most complicated to manufacture and very costly to manufacture.
U.S. Pat. No. 5,030,501 discloses a protective material comprising a plurality of polygonal air-filled cells which are stiffly resilient and interconnected by a stratum or layer of channels to absorb the air displaced by an impact or blow delivered against one or more of the cells which are collapsed as result of the impact thereon. The venting of the cell(s) is for the purpose of reducing the rebound caused by such impact.
None of the prior art disclosures relate to body support cushions capable of omni-directional buffering action but are limited to uniplanar fluid transference.